Treadmill exercising device with yieldable belt support

ABSTRACT

A treadmill exercising machine having an endless belt suspended around horizontally spaced rollers is provided with a resilient and yieldable supporting structure in the form of a plurality of downwardly compressible air cells underlying the upper belt section of the endless belt in supporting relation thereto. A low friction contact sheet disposed between the air cells and upper belt section transmits the weight load of a person walking or running on the upper belt section of the endless belt to the air cells, thereby causing the cells and the air therein to be compressed as the upper belt section is deflected downwardly. The compressed air limits the downward deflection of the belt, and controlled leakage of compressed air between the low friction contact sheet and the upper belt section provides an air bearing effect which reduces the frictional drag of the upper belt section on the contact sheet.

United States Patent Hagen 1 1 Sept. 5, 1972 [54] TREADMILL EXERCISING DEVICE WITH YIELDABLE BELT SUPPORT Primary ExaminerRichard C. Pinltham Assistant ExaminerR. T. Stouffer [72] Inventor: gscar z 6 23rd La Attorney-Williamson, Palmatier & Bains, H. Dale Palmatier, Herman H. Bains and Malcolm L. Moore [22] Filed: Sept. 4, 1970 [21] Appl. No.: 69,574 [57] ABS CT A treadmill exercising machine having an endless belt suspended around horizontally spaced rollers is pro- [52] U. S. Cl ..272/69, 198/184 vided with a resilient d i ldabl supporting struc- [51] Int. Cl. ..A63b 23/06 ture in the f f a plurality f downwardly Fleld of Search "272/69, SS; 94/ 3, 3 S; pressible air cells underlying the upper belt section of 248/353 the endless belt in supporting relation thereto. A low friction contact sheet disposed between the air cells [56] References Cited and upper belt section transmits the weight load of a person walking or running on the upper belt section of UNITED STATES PATENTS the endless belt to the air cells, thereby causing the 3,628,654 12/1971 Haracz ..198/179 Cells thqair therein to be Compressed as the pp 3,319,767 5/1967 Breternitz et al. .....198/l84 x 79 6 9 deflected downwar dly- The compressed 756,600 4/1904 Dodge ..19s/1s4x g i the g contro e ea age 0 compresse air etween e ow FOREIGN PATENTS OR APPLICATIONS friction contact sheet and the upper belt section provides an air bearing effect which reduces the frictional 135,206 4/ 1952 Sweden 0.. ..198/203 drag of the upper belt section on the Contact Sheet 384,019 12/1933 Great Britain ..272/69 1,166,086 3/ 1964 Germany ..198/184 4 Claims, 4 Drawing Figures 13 ll| ..||l\|1|,, lnnm 6 \[1 20 16 24 w 4 1 22 .111 -|1ll|| I 11111..

Patented Sept. 5, 1972 2 Sheets-Sheet 1 INVENTOR.

Patented Sept. 5, 1912 2 Sheets-Sheet 2 I 1 N VEN TOR. 05042 M #46511 Jrroeuzus TREADMILL EXERCISING DEVICE WITH YELDABLE BELT SUPPORT BRIEF SUMMARY OF THE INVENTION section serving as a treading surface on which a person may walk, run or jog for exercising purposes. The endless belt may be rotated around the rollers either by an external power source, or by the walking or running action of a person treading on the upper belt section. The exercising machine is particularly characterized by a resilient and yieldable support structure underlying the upper belt section and providing a cushioning effect as the upper belt section is deflected downwardly under the weight of a person treading thereon while reducing to a minimum the frictional drag of the upper belt section on the support structure as it moves thereover in sliding contact therewith.

These structural and operating advantages are achieved by utilizing a gas cushion to support the aforesaid upper belt section of the endless belt, the gas cushion preferably taking the form of a plurality of collapsible bellows cells having a gaseous medium therein. The downward deflection of the aforesaid upper belt section under the weight load of a person treading thereon compresses both the underlying bellows cells and the gaseous medium therein, whereby the downward deflection of said upper belt section is limited. The resiliency of the bellows cells permits them to expand upwardly as the upper belt section rebounds upwardly upon removal of the weight load thereon, whereby the bellows cells and the gaseous medium therein alternately compress and expand to provide a desirable cushioning effect for the upper belt section as it flexes upwardly and downwardly.

As a particularly beneficial aspect of my improved treadmill exerciser, the aforesaid bellows cells are joined together at their upper ends to form a common cellular structure by means of an overlying sheet of low friction, pliable material which serves as a contact surface against which said upper belt section slides under the weight of a person walking or running thereon.

A particularly advantageous feature of the treadmill exerciser of this invention resides in the provision of a thin film of pressurized gas between the underside of the upper belt section of the treadmill and an underlying, low friction contact surface to thereby achieve an air bearing effect, greatly reducing the frictional drag on the endless belt. Utilizing air as the gaseous medium in the aforesaid bellows cells, the air bearing effect is accomplished by employing a low friction sheet of pliable material as the aforesaid contact surface for the upper belt section of the treadmill and permitting a limited amount of pressurized air to flow out of the bellows cells between the upper belt section and the low friction sheet during compression of the cells. A plurality of apertures are formed in the low friction contact sheet, and the sliding contact of the upper belt sec tion with said sheet under load provides a slow leaking air seal at each of said apertures through which a controlled amount of pressurized air flows upwardly to provide an air bearing under the upper belt section. Each of the bellows cells is also provided with an air intake check valve communicating with the atmosphere, said check valves being closed upon the compression of the bellows cells and opening to permit a predetermined air inflow into the cells upon the upward movement of the upper belt section and the expansion of the bellows cells.

These and other objects and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings wherein like reference numerals have been used to designate like elements throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top, plan view showing one end of the treadmill exercising machine of this invention;

FIG. 2 is a side elevation view of the treadmill machine of FIG. 1;

FIG. 3 is a perspective view, partially broken away, showing the support structure for the upper belt section of the treadmill exercising machine; and

FIG. 4 is a vertical section view of the upper belt section support structure taken along lines 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The exercising machine of this invention is of the treadmill type, and as is shown in FIGS. 1 and 2, incorporates an endless belt generally indicated by reference numeral 1 which is looped around a pair of horizontally spaced rollers 2 and 3 and suspended therebetween. There will thus be provided a lower, horizontally extending belt section 1a and an upper belt section 1b extending horizontally thereover. A person utilizing the exercising machine will walk, run or jog on upper belt section lb. Bearings 4 and 5 rotatably support horizontally extending roller shafts 6 and 7, bearings 4 and 5 being mounted on top of elongated side beams 8 of a base frame assembly including legs 10 on which the entire exercising machine is mounted. It will be appreciated that with rollers 2 and 3 revolving in a direction indicated by the arrows in FIG. 2, upper belt section 1b will move generally horizontally in a right to left direction.

Motive power for revolving belt 1 can be supplied either by the person exercising or by an external power source. Ifthe belt is to be moved by the person exercising, then the entire exercising machine would be mounted in an inclined position, rather than horizontally as shown in FIG. 2. Such inclined, self propelled treadmills are well known, and such an arrangement has not been shown since the particular manner of driving the endless belt is of no significance with respect to the treadmill of this invention. I prefer to utilize a variav ble speed motor 12 to drive endless belt 1, motor 12 having an output shaft 14 on which a drive pulley 16 is mounted. A driven pulley 18 is mounted on front roller drive shaft 6, and belt 20 extending around pulleys 16 and 18 is utilized to impart rotational movement to front roller 2 from drive motor 12. The speed of motor 12 may be adjusted by well known control arrangements (not shown) by the operator to set the linear speed of upper belt section 1b to achieve the degree and intensity of exercise desired, such as walking, jogging or running at a rapid pace.

The base frame assembly for the exercising machine also includes a plurality of transversely extending cross braces 22 on which are supported a pair of laterally spaced top beams 24, one of which is shown in FIG. 2. Elongated, top beams 24 are mounted under upper belt section 1b and support a rigid base plate 26 on which is mounted a resilient and yieldable support structure for upper belt section lb, which will now be described with reference to FIGS. 3 and 4.

In the perspective view of FIG. 3, and the section view illustrated in FIG. 4, I have shown rigid base plate 26 and upper belt section 1b with the resilient and yieldable back-up support structure therebetween. Endless belt 1 may be formed in various ways. In the preferred embodiment shown, the endless belt is comprised of an outer rubber strip 28, an intermediate cord ply layer 30 and a steel ply 32. Steel ply 32 is optional, and may be utilized to lend strength to the endless belt 1 and render it more self supporting under the weight load of person treading thereon. Rubber strip 28 is preferably notched transversely as indicated in FIGS. 3 and 4 so that belt 1 may more easily bend around rollers 2 and 3.

In order to limit the downward deflection of upper belt section 1b under maximum load conditions, such as when a persons foot is pressed downwardly on endless belt 1 during jogging or running exercising motion, and to closely simulate actual running condition on a level surface such as a road, a resilient and yieldable back-up support structure is utilized under upper belt section 1b in supporting relation thereto. For this purpose, I have found that a compressible gas cushion comprised of chamber means having a gaseous medium therein is particularly effective. In the preferred embodiment of my invention shown in FIGS. 3 and 4, the gas cushion structure advantageously takes the form of a plurality of vertically collapsible bellow cells 34 having air therein as the gaseous medium. Cells 34 may be made from various flexible materials such as rubber, nylon or sheet metal. Some type of plastic material, such as nylon, is preferred. The bottom ends of each of the bellows cells 34 rest upon and are attached to the upper surface of rigid base plate 26, an adhesive material being conveniently utilized to secure the bottom edges of cells 34 to the top face of plate 26. For a purpose hereinafter explained, a plurality of air ports 36 are formed in base plate 26 directly under each of the bellows cells 34 in fluid flow communication therewith. Disposed within each of the bellows cells 34 is a reed valve 38 having its base end affixed to the upper face of base plate 26, as by welding, and having a flexible valve end 38a in overlying, flow control relation to air ports 36. Reed valves 38 serve as one-way check valves which operate to close ports 36 upon the downward compression of bellows cells 34 and the air therein, and which open upon the upward expansion of bellows cells 34 to admit air through ports 36. At their upper ends, each of the bellows cells 34 bears against the underside of an overlying, low friction sheet 40 in supporting engagement therewith. The top, outwardly turned terminal flanges 34a of cells 34 are affixed to the underside of sheet 40, preferably by an adhesive material. Alternatively, I contemplate that bellows cells 34 and sheet 40 may be molded integrally from plastic material for manufacturing convenience and economy.

Stationary, low friction sheet 40 lies directly under upper belt section lb and serves as a contact surface against which upper belt section 1b slides under the weight of a person walking or running thereon. Sheet 40 may be formed from various materials having a low friction coefficient. I have found it desirable to use a nylon sheet having a teflon coating thereon to provide a minimum of frictional drag against belt section lb. The attachment of bellows cells 34 to overlying plastic sheet 40 joins the plurality of bellows cells together in a common cellular structure, sheet 40 serving to transmit the downward weight load of a person treading on belt section lb to collapsible bellows cells 34 and the air therein.

Formed in plastic sheet 40 are a plurality of apertures 42, each of which is disposed in vertical alignment with one of the bellows cells 34 in fluid flow communication therewith. For the purpose of permitting a predetermined amount of air leakage out of cells 34 during compression thereof, I provide a plurality of transversely extending grooves 44 connecting each of the apertures 42, and a plurality of longitudinally extending grooves 46 interconnecting with transverse grooves 44 and extending to the laterial, peripheral edges of plastic sheet 40. Under load, upper belt section 1b contacts plastic sheet 40 and forms a slow leaking seal at each of the apertures 42, a limited amount of air being permitted to escape through interconnecting leakage grooves 44 and 46.

In operation, the combination of perforated sheet 40, bellows cells 34 and upper belt section 1b provides a means for compressing the air contained in cells 34 to thereby give a resilient and yieldable air cushion support to upper belt section 1b. As the weight load of a person walking, running or jogging on endless belt 1 is applied downwardly to upper belt section lb, the belt deflects downwardly as it moves in sliding contact with low friction plastic sheet 40. The downward deflection of upper belt section 1b under load compresses both the underlying bellows cells 34 and the air within the cells, check valves 38 being closed under downward pressure. The pressurized air within cells 34 gives upward support to belt section lb and limits the downward deflection thereof under load. The resilient material-from which bellows cells 34 are constructed permits these cells to flex vertically and to expand up wardly to their normal shape and height when the compression load thereon is removed, as when a persons foot is lifted upwardly during walking or running action on belt section lb. In this manner, bellows cells 34 dampen and limit belt motion in the downward direction.

It is also highly desirable to limit the upward movement of upper belt section 1b, since the high strength belt 1, tensioned around end rollers 2 and 3 will tend to vibrate vertically when loaded in a cyclic manner by the running movement of a person on the moving belt surface. Underlying air cells 34 also accomplish this desirable effect in the following manner. During the downward movement of upper belt section lb, while air cells 34 is being compressed, some air leakage takes place from the cells through apertures 42 and grooves 44 and 46 to the atmosphere. As noted above, grooves 44 and 46 provide a slow leaking sealing effect between upper belt section 1b and plastic sheet 40 at apertures 42 when belt section lb is under downward load. Upon the upward movement of belt section 1b, bellows cells 34 will expand upwardly; and before cells 34 return to their normal height, the internal air pressure therein will become atmospheric, since some air leaked out during compression. The remaining upward travel of belt section lb causes a pressure reduction in air cells 34 below atmospheric. Thus, with a higher, atmospheric pressure above belt section 1 b and a slight vacuum created thereunder, there will be a pressure differential on belt section 1b in a downward direction tending to limit its upward deflection. The amount of vacuum created in the bellows cells 34 is regulated by the air bleed rate of valves 38 in the bottom of the bellows cells, as well as by the amount of air leakage out of each of the cells during compression. It will be appreciated that as bellows cells 34 expand upwardly, flexible valve ends 382 of reed valves 38 will be urged upwardly to permit air to be introduced through ports 36 into cells 34 from the surrounding atmosphere. Air leakage out of bellows cells 34 between a plastic sheet 40 and belt section 1b during the compression of cells 34 can be controlled by the size of leakage grooves 44 and 46.

It will be appreciated that the operation of bellows cells 34 in the foregoing manner greatly stabilizes the running or walking surface defined by upper belt section lb by dampening out the inherent springy effect of suspended belt section 1b. Thus, not only does the resilient and yieldable support structure formed by bellows cells 34 provide an air cushion relieving strain on a persons legs as he runs or walks on belt section lb, but this particular air cushion support structure also limits the vertical vibration of belt section lb so as to more nearly simulate a level running surface. Moreover, the mechanical stresses, particularly the bending stresses on belt 1 under load are greatly reduced as a result of minimizing vertical deflection of upper belt section lb.

A further operating advantage is achieved by the slow leakage of pressurized air from bellows cells 34 between low friction contact sheet 40 and upper belt section lb. The thin film of pressurized air flowing over contact sheet 40 when bellows cells 34 are under compression provides an air bearing effect under upper belt section 11) to allow belt 1 to slide freely over contact sheet 40. This air bearing in combination with the low friction coefficient of contact sheet 40 insures a minimum of frictional drag on moving belt 1. As a result, the power requirements for drive motor 12 to propel endless belt 1 around rollers 2 and 3 are greatly reduced.

I claim:

1. A treadmill exercising device comprising:

an endless belt looped around horizontally spaced roller support means, thereby providing a lower belt section and an overlying upper belt section on which a person may run or walk;

a low friction sheet of pliable material lying under said upper belt section and serving as a contact surface against which said upper belt section slides, said low friction sheet being freely displaceable upwardly and downwardly over its entire area and sufiiciently pliable as to yield downwardly under the weight load of a person on said upper belt section, and said upper belt section being in direct contact with said low friction sheet and supported entirely thereon over the entire area of said upper belt section in its unloaded state; and

resilient and yieldable support means disposed under said sheet of pliable material over its entire area in supporting relation thereto and depressible therewith under the weight of a person walking or running on said upper belt section.

2. A treadmill exercising device as defined in claim 1 wherein:

said resilient and yieldable support means comprises a gas cushion in the form of a plurality of collapsible bellows cells having a gaseous medium therein, each of said bellows cells having a flexible side walls abutting at their bottom ends against afixed base with their upper ends bearing against the underside of said low friction sheet of pliable material in supporting engagement therewith, said sheet of pliable material being supported over its entire area entirely on said bellows cells, whereby the downward deflection of said upper belt section under load compresses both the underlying bellows cells and the gaseous medium therein, the pressurized gaseous medium resisting further downward depression of said upper belt section and giving upward support thereto.

3. A treadmill exercising device as defined in claim 2 wherein:

said gaseous medium in each of said bellows cells is air; and further including an air intake check valve in each of said bellows cells communicating with the atmosphere, said check valves being closed upon the compression of said bellows cell and the air therein, and said check valves opening to permit a predetermined air inflow into said cells upon the upward movement of said upper belt section and the expansion of said bellows cells.

4. A treadmill exercising device comprising:

an endless belt looped around horizontally spaced roller support means, thereby providing a lower belt section and an overlying upper belt section on which a person may run or walk;

a low friction sheet of pliable material lying under said upper belt section and serving as a contact surface against which said upper belt section slide;

a resilient and yieldable support means in the form of a gas cushion under said sheet of pliable material, said gas cushion comprising a plurality of collapsible bellows cells having air therein as a gaseous medium, said bellows cells having their bottom ends resting upon a fixed base with their upper ends bearing against the underside of said low friction sheet of pliable material in supporting engagement therewith, whereby the downward deflection of said upper belt section under load compresses both the underlying bellows cells and the air therein; 7

an air intake valve in each of said bellows cells communicating with the atmosphere, said check valves being closed upon the compression of said bellows cells and the air therein, and said check valves opening to permit a predetermined air inflow into said cells upon the upward movement of said upper belt section and the expansion of said bellows cells; and

pressurized air to leak out of said bellows cells through said apertures during compression of said cells to provide an air bearing in the form of a thin film of pressurized air between said upper belt section and said low friction sheet. 

1. A treadmill exercising device comprising: an endless belt looped around horizontally spaced roller support means, thereby providing a lower belt section and an overlying upper belt section on which a person may run or walk; a low friction sheet of pliable material lying under said upper belt section and serving as a contact surface against which said upper belt section slides, said low friction sheet being freely displaceable upwardly and downwardly over its entire area and sufficiently pliable as to yield downwardly under the weight load of a person on said upper belt section, and said upper belt section being in direct contact with said low friction sheet and supported entirely thereon over the entire area of said upper belt section in its unloaded state; and resilient and yieldable support means disposed under said sheet of pliable material over its entire area in supporting relation thereto and depressible therewith under the weight of a person walking or running on said upper belt section.
 2. A treadmill exercising device as defined in claim 1 wherein: said resilient and yieldable support means comprises a gas cushion in the form of a plurality of collapsible bellows cells having a gaseous medium therein, each of said bellows cells having a flexible side walls abutting at their bottom ends against a fixed base with their upper ends bearing against the underside of said low friction sheet of pliable material in supporting engagement therewith, said sheet of pliable material being supported over its entire area entirely on said bellows cells, whereby the downward deflection of said upper belt section under load compresses both the underlying bellows cells and the gaseous medium therein, the pressurized gaseous medium resisting further downward depression of said upper belt section and giving upward support thereto.
 3. A treadmill exercising device as defined in claim 2 wherein: said gaseous medium in each of said bellows cells is air; and further including an air intake check valve in each of said bellows cells communicating with the atmosphere, said check valves being closed upon the compression of said bellows cell and the air therein, and said check valves opening to permit a predEtermined air inflow into said cells upon the upward movement of said upper belt section and the expansion of said bellows cells.
 4. A treadmill exercising device comprising: an endless belt looped around horizontally spaced roller support means, thereby providing a lower belt section and an overlying upper belt section on which a person may run or walk; a low friction sheet of pliable material lying under said upper belt section and serving as a contact surface against which said upper belt section slide; a resilient and yieldable support means in the form of a gas cushion under said sheet of pliable material, said gas cushion comprising a plurality of collapsible bellows cells having air therein as a gaseous medium, said bellows cells having their bottom ends resting upon a fixed base with their upper ends bearing against the underside of said low friction sheet of pliable material in supporting engagement therewith, whereby the downward deflection of said upper belt section under load compresses both the underlying bellows cells and the air therein; an air intake valve in each of said bellows cells communicating with the atmosphere, said check valves being closed upon the compression of said bellows cells and the air therein, and said check valves opening to permit a predetermined air inflow into said cells upon the upward movement of said upper belt section and the expansion of said bellows cells; and a plurality of apertures in said low friction sheet in fluid flow communication with each of said bellows cells, the sliding contact of said upper belt section with said low friction sheet under load providing a slow leaking air seal at each of said apertures, thereby permitting a limited amount of pressurized air to leak out of said bellows cells through said apertures during compression of said cells to provide an air bearing in the form of a thin film of pressurized air between said upper belt section and said low friction sheet. 